Fast Forward three years (2004):
Pole position Driver Michael Schumacher Ferrari Time 1:24.408 Fastest lap Driver Michael Schumacher Ferrari Time 1:24.125 on lap 29
I think the 2004 cars were too fast. But sure, let's keep fast-forwarding:
The fastest lap average speed in 2001 was 216.4 km/h
The fastest lap average speed in 2004 was 226.9 km/h
Average gain per year was 3.506 km/h
So the fastest lap average speed in 2017 should be 272.5 km/h